Calculate the area of a rectangle, the perimeter of which is 20m, and the length of one side is 4 times the length of the other side.

1) Find the sides of the rectangle. Let one side of the rectangle be x cm, then the other side of the rectangle is 4x cm. The perimeter of the rectangle is 2 (x + 4x) cm or 20 cm. Let’s make an equation and solve it.

2 (x + 4x) = 20;

2 * 5x = 20;

10x = 20;

x = 20: 10;

x = 2 (cm) – length of one side;

4x = 2 * 4 = 8 (cm) – the length of the second side.

2) find the area of the rectangle. The area of a rectangle is equal to the product of its sides (length and width).

S = 2 * 8 = 16 (cm ^ 2)

Answer. 16 cm ^ 2.